In this work, we aim to quantify the relevance of kinematically identified bulges and discs and their role in the process of galaxy quenching. To achieve this, we utilised an analysis of the SDSS-MaNGA survey conducted with the GPU-based code bang which simultaneously models galaxy photometry and kinematics to decompose galaxies into their structural components. We found that below M? ' 1011 M , galaxies span a wide range in their dynamical properties. The overall dynamical state of a galaxy is determined by the relative prominence of a dispersion-supported inner region and a rotationally supported disc. Our decomposition reveals a natural separation between these classes, with only a minor fraction of stellar mass retained by structures exhibiting intermediate dynamical support. When examining galaxies in terms of their star formation activity, an apparent substantial decrease in rotational support is observed as they move below the star-forming main sequence. This behaviour is particularly evident when using luminosity-weighted tracers of kinematics, while it almost vanishes with mass-weighted tracers. Luminosity-weighted quantities not only capture differences in kinematics but also in the stellar population, potentially leading to biased interpretations of galaxy dynamical properties and quenching. Our findings indicate that quenching implies almost no any structural transformation in galaxies below M? ' 1011 M . Processes such as disc fading are more likely explanations for the observed differences in mass-weighted and luminosity-weighted galaxy properties. When the galactic disc ceases star formation, its mass-to-light ratio does indeed increase without any significant morphological transformation. The picture is remarkably different above M? ' 1011 M . In this case, regardless of the tracer used, a substantial increase in galaxy dispersion support is observed along with a significant structural change. A different quenching mechanism, most likely associated with mergers, dominates. Notably, this mechanism is confined to a very limited range of high masses.

BANG-MaNGA: A census of kinematic discs and bulges across mass and star formation in the local Universe

Fabio Rigamonti
;
Francesco Bollati;Stefano Covino;Massimo Dotti;Francesco Haardt
2024-01-01

Abstract

In this work, we aim to quantify the relevance of kinematically identified bulges and discs and their role in the process of galaxy quenching. To achieve this, we utilised an analysis of the SDSS-MaNGA survey conducted with the GPU-based code bang which simultaneously models galaxy photometry and kinematics to decompose galaxies into their structural components. We found that below M? ' 1011 M , galaxies span a wide range in their dynamical properties. The overall dynamical state of a galaxy is determined by the relative prominence of a dispersion-supported inner region and a rotationally supported disc. Our decomposition reveals a natural separation between these classes, with only a minor fraction of stellar mass retained by structures exhibiting intermediate dynamical support. When examining galaxies in terms of their star formation activity, an apparent substantial decrease in rotational support is observed as they move below the star-forming main sequence. This behaviour is particularly evident when using luminosity-weighted tracers of kinematics, while it almost vanishes with mass-weighted tracers. Luminosity-weighted quantities not only capture differences in kinematics but also in the stellar population, potentially leading to biased interpretations of galaxy dynamical properties and quenching. Our findings indicate that quenching implies almost no any structural transformation in galaxies below M? ' 1011 M . Processes such as disc fading are more likely explanations for the observed differences in mass-weighted and luminosity-weighted galaxy properties. When the galactic disc ceases star formation, its mass-to-light ratio does indeed increase without any significant morphological transformation. The picture is remarkably different above M? ' 1011 M . In this case, regardless of the tracer used, a substantial increase in galaxy dispersion support is observed along with a significant structural change. A different quenching mechanism, most likely associated with mergers, dominates. Notably, this mechanism is confined to a very limited range of high masses.
2024
2024
galaxies: bulges; galaxies: kinematics and dynamics; galaxies: photometry; galaxies: star formation; galaxies: statistics; galaxies: structure
Rigamonti, Fabio; Cortese, Luca; Bollati, Francesco; Covino, Stefano; Dotti, Massimo; Fraser-McKelvie, A.; Haardt, Francesco
File in questo prodotto:
File Dimensione Formato  
_BANGMaNGA-A-census-of-kinematic-discs-and-bulges-across-mass-and-star-formation-in-the-local-UniverseAstronomy-and-Astrophysics.pdf

accesso aperto

Tipologia: Versione Editoriale (PDF)
Licenza: Creative commons
Dimensione 778.16 kB
Formato Adobe PDF
778.16 kB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11383/2171253
 Attenzione

L'Ateneo sottopone a validazione solo i file PDF allegati

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 2
  • ???jsp.display-item.citation.isi??? 2
social impact